Sizing of magnetite pile on steam generator tubing with two-probe eddy current technique

Tarja Jäppinen, Kari Lahdenperä

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    During in-service inspection the steam generator tubes are generally inspected using single probe eddy current techniques. Magnetite deposit built up on the outer surface of the tubes can be detected with the applied techniques. As deposits grow thicker they tend to split as flakes from the surface of the tubes. These flakes often build magnetite piles between the tubes. The piles restrict free flow of secondary water. Under magnetite piles the conditions are also favourable for corrosion induced defect initiation and growth on the outer surface of the steam generator tubing. The height of the magnetite piles cannot be sized properly with the standard single probe techniques. In this study experiments were conducted to size the height of the magnetite piles. For this purpose a small simple steam generator mock-up with parallel tubes was constructed. Flake piles of magnetite deposits were heaped up between the tubes. A developed two probe technique was used. In this technique two eddy current probes are pulled simultaneously through two neighbouring tubes. The probes were axially aligned. The test showed that the pile of the magnetite can be located and its height can be estimated with two-probe technique. The results of the experiments are presented.
    Original languageEnglish
    Title of host publicationProceedings of the 10th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components
    ISBN (Electronic)978-92-79-25281-5
    Publication statusPublished - 2013
    MoE publication typeNot Eligible
    Event10th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components - Cannes, France
    Duration: 1 Oct 20133 Oct 2013

    Conference

    Conference10th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components
    CountryFrance
    CityCannes
    Period1/10/133/10/13

    Keywords

    • eddy current
    • steam generator
    • magnetite

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  • Cite this

    Jäppinen, T., & Lahdenperä, K. (2013). Sizing of magnetite pile on steam generator tubing with two-probe eddy current technique. In Proceedings of the 10th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components https://www.ndt.net/article/jrc-nde2013/papers/361.pdf